1. Field of the Invention
The present invention relates to a data link module of a communication device for inputting and outputting an electrical signal or an optical signal. More particularly, the present invention relates to a data link module with a structure for locking the module.
2. Description of the Related Art
A communication device for inputting and outputting an electrical signal or an optical signal is designed in module, and a module structure capable of inserting and removing a module to and from a module-receiving cage is known. Examples of known communication devices designed in module include a module for converting an electrical data signal into an optical signal for transmission of the optical signal via an optical fiber, and a module for converting an optical signal received via an optical fiber into an electrical data signal.
In the field of optical communication devices always aiming at a further size reduction, standardization of component specifications is under progress and standards are specified regarding dimensions of modules and cages, compatibility of optical/electrical interface units, mechanical compatibility in inserting and removing modules to and from cages, etc.
FIG. 1 is a perspective view showing one structure of a mechanism for inserting and removing a modular optical communication device according to the related art.
Referring to FIG. 1, a removable optical module 1 is inserted in a cage 4. The optical module 1 comprises a printed board 13 including various devices mounted on it, an optical interface section 12 disposed at one end of the optical module in the lengthwise direction thereof, an electrical interface section 14 disposed at the other end of the optical module in the lengthwise direction thereof, and a housing 2 encasing the printed board 13, etc.
The printed board 13 mounts thereon various devices constituting an opto-electric converting circuit, and a power supply circuit. The optical interface section 12 disposed at one end of the optical module 1 in the lengthwise direction thereof is exposed to the exterior even in the state, shown in FIG. 1, where the optical module 1 is inserted in the cage 4. An optical fiber cable (not shown) is coupled to the optical interface section 12.
The electrical interface section 14 disposed at the other end of the optical module 1 in the lengthwise direction thereof has a printed contact 141 formed at an end of the printed board 13. In the state, shown in FIG. 1, where the optical module 1 is inserted in the cage 4, the printed contact 141 is fitted to a card edge connector provided in, e.g., a mother board (not shown) to which the cage 4 is attached.
The housing 2 serves to provide an electromagnetic shield and/or mechanical protection for the printed board 13, an optical connector, etc. which are mounted on the optical module 1. The housing 2 is fitted in the lengthwise direction so as to cover the optical module 1 from three directions except for a bottom surface or to entirely cover the optical module 1.
The optical module 1 capable of being inserted into and removed from the cage 4, shown in FIG. 1, includes a mechanism for inserting and removing the optical module 1 into and from the cage 4, and a mechanism for locking the module 1 to the cage 4 when the module is inserted in the cage.
In the state where the optical module 1 is inserted in the cage 4 as shown in FIG. 1, the optical module 1 and the cage 4 are locked to each other upon engagement of a lock pin 122 projecting on one wall surface of the optical module 1 into a lock hole 43 bored in a corresponding wall surface of the cage 4.
The optical module 1 can be removed from the cage 4 by disengaging the lock pin 122 from the lock hole 43, and then withdrawing the optical module 1 while grasping a bail 3. To withdraw the optical module 1 in the direction of arrow 53, the bail 3 is erected (turned angularly) in the direction of arrow 51 from a retracted state.
Here, when the optical module 1 is pushed and inserted in the cage 4, the lock pin 122 is spontaneously engaged in the lock hole 43 for locking between them, and when the bail 3 is erected in the direction of arrow 51, the lock pin 122 is disengaged from the lock hole 43 for unlocking. Accordingly, the optical module 1 can be easily removed from the cage 4 by withdrawing the bail 3 in the direction of arrow 53. In other words, the inserting/removing operation and the locking/unlocking operation for the optical module 1 and the cage 4 can be performed in an interlocked manner.
In one known mechanism for realizing those interlocked operations, the bail is disposed at front face of the optical module. When the bail is erected for withdrawing the bail forward, the lock pin is retracted following to the erecting movement of the bail such that the lock pin is disengaged from the lock hole.
That known mechanism is practically constituted as follows. The lock pin is projected at one end of a pivot block on one side of a shaft thereof, and the other end of the pivot block is engaged with a cam mechanism of the bail. When the bail is erected to withdraw the optical module from the cage, the other end of the pivot block is pushed up by the cam mechanism of the bail. As a reaction, one end of the pivot block is pushed down, whereupon the lock pin is retracted and disengaged from the lock hole.
In another example of known mechanisms for engaging and disengaging the lock pin with rotation of the bail, when the bail is erected, a push tab is moved and a boss is pushed down through an actuator that is caused to swing following to the movement of the push tab. Correspondingly, the lock pin is retracted and disengaged from the lock hole.
In still another example of known mechanisms for engaging and disengaging the lock pin with rotation of the bail, when the bail is erected, a slider is forced to slide to push up a tongue provided in the cage. Correspondingly, the lock pin fixedly provided on the module is disengaged from the tongue provided in the cage.
Thus, as mechanisms for unlocking the optical module from the cage when the optical module is inserted into and removed from the cage, there are known structures of withdrawing the lock pin by utilizing the torque caused when erecting the bail, the cam mechanism, and so on. In those mechanisms, however, because the lock pin is retracted with the operation of the bail, movements of the lock pin other than the vertical movement must be restricted and a plurality of movable members must be interposed between the bail and the lock pin.
Stated another way, the structure of retracting the lock pin with the operation of the bail necessarily increases the number of parts, thus resulting in the increased cost of those required parts, more complicated assembly, and hence the increased number of manufacturing steps.
Further, the dimensions of the optical module and the cage are limited, and a further reduction in size of the locking and unlocking mechanisms is demanded. From this point of view, it is disadvantageous to dispose a plurality of movable members between the bail and the lock pin.
In the case employing, as the mechanism for unlocking the optical module from the cage, the mechanism of pushing up the tongue provided in the cage, this pushing-up mechanism must be designed so as to take a position where biasing against the tongue provided in the cage is released in the stationary state.
To release that biasing, however, an operator must push the bail by a finger to bring the biasing mechanism into the release position, thus resulting in troublesome operation.
Accordingly, it is an object of the present invention to provide a data link module capable of autonomously realizing, with a simple mechanism, the position where biasing against a tongue provided in a cage is released.